垂直交叉双圆柱绕流强迫振动数值模拟

采用虚拟体法数值模拟了平面单圆柱绕流强迫振动,以及空间垂直交叉双圆柱绕流下游圆柱强迫振动流场。验证了单圆柱强迫振动中的锁定状态以及相位突变现象,从而证实了该数值方法模拟振动流场的可靠性。研究了在雷诺数Re=150、间距为5倍圆柱直径、下游圆柱按正弦曲线振动时,对尾流场的影响。下游圆柱两端尾流场在振动的作用下,涡的横向间距增大,而中心尾流场由于受上游圆柱尾流的影响而保持原先的状态。下游圆柱在锁定区的振动使尾流场变得稳定,表现在流向二次涡结构的减少,以及尾流场的速度场频谱趋向单一化。

Numerical simulations of Forced oscillations of two circular cylinders in cruciform arrangement

The virtual body method is applied to simulate the flow passing around a single oscillating circular cylinder and two circular cylinders in cruciform arrangement with the downstream one forced oscillating.The synchronization and phase 'jump' phenomena are observed in a single oscillating circular and confirm the validity of this numerical method for simulations of oscillating problems. For flow past two cylinders in cruciform arrangement,when Re=150 and the spacing between axes of two cylinders 5 diameters,vortex shedding from the transversely oscillating downstream cylinder is studied.When transverse vortex spacing of the end part of flow wake from downstream cylinder is increased,the center part of flow wake keeps the former state because of the influence of upstream cylinder.In synchronization region,the oscillations make the wake of downstream cylinder stable,behave as that the streamwise vortex structures are reduced and the spectra of the flow wake come into only single predominating frequency.